There are multiple discussions on this message board regarding pronation and its importance in everything from the forehand to the serve. All of this has led me, the average tennis player, to wonder: What exactly is pronation? And furthermore, Is it something that occurs naturally during the serve or groundstroke motion, or is it something that must be learned and integrated into the motion? Also, it seems that if one was to ask three different people, he/she would receive three different definitions as to what pronation really is. So, is there one clear definition of pronation? If so I need to be enlightened with a clear indisputable definition and how it is important to all the facets of tennis. So if anyone here has the downlow on pronation, please help me out here and explain.